1. Field of the Invention
This invention relates to organo-metallic compounds and, more specifically, to the composition and preparation of 2-bromoethyl tellurium bromides.
2. Description of the Prior Art
Organo-tellurium compounds are valuable in the preparation of a wide variety of chemicals, and reactions between organic compounds and tellurium compounds to form organo-tellurium have been studied. However, these reactions are not yet completely understood, due to the complexities of tellurium chemistry. Thus, while reactions between tellurium tetrachloride and certain olefins have been reported to result in organo-tellurium compounds, the same reactions have not been found to necessarily occur with tellurium tetrabromide.
C. H. Fisher et al., J. Org. Chem., vol 6, pp. 169-174 (1941) found TeCl.sub.4 to react in benzene with cyclohexene and styrene exothermically to form high molecular weight, polymeric products. Addition products between TeCl.sub.4 and cyclohexene were identified in M. de Moura Campos, et al., Tetrahedron Letters No. 6, pp. 11-13 (1959) and Masao Ogawa, Bull. Chem. Soc. Jap. vol. 41, p. 3031 (1968), although these researchers disagreed on the type of addition product obtained. M. de Moura Campos, et al., Tetrahedron, vol. 18, pp. 521-526 (1962) found unidentified products and elemental tellurium to be formed in the reaction of TeCl.sub.4 with diisobutylene, styrene and 1,4-diphenyl-butadiene-1,3. M. Ogawa, Bull. Chem. Soc. Jap., vol. 41, p. 3031 (1968), M. Ogawa et al., Bull. Chem. Soc. Jap., vol. 43, pp. 496-500 (1970) and H. J. Arpe, et al., Angew Chem. Internat. Edit., vol. 10, pp. 73-75 (1971) found a mixture of organo-halogens to result in the reaction of TeCl.sub.4 with butene-1, propylene and ethylene, respectively. For example, TeCl.sub.4 was found by Arpe et al., to sluggishly react with ethylene in CCl.sub.4 at 20.degree.-60.degree. C. to form a mixture of Cl.sub.2 Te(CH.sub.2 CH.sub.2 Cl).sub.2 and Cl.sub.3 TeCH.sub.2 CH.sub.2 Cl, and Ogawa et al., found a mixture of ##STR1## to be formed in the reaction of propylene and TeCl.sub.4.
However, W. V. Farrar, et a., J. Chem. Soc., pp. 11-14 (1945) did not obtain .beta.,.beta.'-dihalogen diethyl telluride derivatives by reacting ethylene with TeBr.sub.4 in either CCl.sub.4 or HBr. Kurt J. Irgolic, The Organic Chemistry of Tellurium, (1974) has summarized the art as showing that TeBr.sub.4 does not react with ethylene (pp. 36, 172).
Dialkyl tellurium dibromides have been prepared by reacting dialkyl tellurium dinitrates or hydroxy chlorides with HBr, and (CH.sub.3).sub.2 TeBr.sub.2 has been formed by the reaction of a mercuric halide addition compound with NaOH followed by treatment with HBr. Tellurium, pp. 235-243 (W. Charles Cooper, et.; Van Nostrand Reinhold Co. 1971).
Inorganic tellurium compounds have been heretofore contacted with ethylene in the presence of carboxylic acid and dissolved bromine in liquid reaction media, e.g., in processes disclosed in U.S. Pat. Nos. 3,262,969; 3,668,239; 3,689,535; 3,715,388; 3,715,389; 3,743,672; 3,770,813; 3,778,468 and 3,907,874, in which the olefin is reacted with a carboxylic acid and molecular oxygen in the presence of a co-catalyst system comprising a variable valent metal cation (e.g., Te) and a halide (e.g., Br) to form ethylene glycol carboxylic acid esters.
Preparation of organo-metallic compounds from olefins and other elements of Group VIA of the Periodic Table, e.g., Se, have also been studied. See, e.g., Carl E. Frick, J. Amer. Chem. Soc., vol. 45, pp. 1795-1799 (1923) (selenium oxychloride+ethylene.fwdarw.bis(.beta.-chloro-ethyl)selenium dichloride; H. C. Bell, et al., J. Chem. Soc., 1877 (1925) (SeBr.sub.4 +ethylene.fwdarw.Br.sub.2 Se(CH.sub.2 CH.sub.2 Br).sub.2); H. L. Riley, et al., J. Chem. Soc., pp. 2342-2344 (1932) (ethylene+HCl+SO.sub.2 .fwdarw.Cl.sub.2 Se(CH.sub.2 CH.sub.2 Cl).sub.2); and D. H. Olson, Tetrahedron Letters, No. 19, pp. 2053-2058 (1966) (ethylene+acetic acid+SeO.sub.2 .fwdarw.ethylene glycol diacetate, bis(.beta.-acetoxy ethyl)selenide and bis(.beta.-acetoxy ethyl)diselenide).